The present invention relates to a character recognition equipment for imprints, printed matter and stamped characters, and more particularly to a character recognition equipment suitable for recognizing characters having poor contrast between the characters and the background and having varied printing quality.
Conventional character recognition equipment utilizes an application of a pattern matching method in which a character pattern is divided in a plurality of sections and recognition judgement is made by comparing and collating the degree of resemblance for every division unit as described in Japanese Patent Laid-Open No. 61-255488 for instance. This method is a recognition algorithm using a binary image. When a change such as breaking and thinning are produced in a character's line, processing becomes complicated and recognition time becomes longer because such variation is absorbed by the recognition algorithm. For example, a binarized threshold also becomes unable to correspond to characters printed with varying quality with a fixed threshold. Besides, such recognition algorithm is performed by classifying extracted features in accordance with a judgement tree, but the way of combining these features for obtaining an optimum judgement has been obtained through experiments in a trial-and-error manner. Since the above-described conventional technique depends on the application of a pattern matching method and is a recognition algorithm using a binary image, a satisfactory result is obtainable for character recognition of paper with good printing quality and the like. However, when the contrast of characters to be recognized is poor and breaking and thinning are produced when binarized there are problems. The recognition algorithm thereof becomes complicated, thus making the recognition time longer and the misrecognition rate higher.